On Wednesday, November 05, 2014 09:53:59 AM Prarit Bhargava wrote:
> Add some additional debug to capture failures in the locking scheme for
> cpufreq. Instead of just a NULL pointer, these warnings will capture failure
> points if the locking scheme for cpufreq is broken.
>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Viresh Kumar <[email protected]>
> Cc: [email protected]
> Signed-off-by: Prarit Bhargava <[email protected]>
> ---
> drivers/cpufreq/cpufreq_governor.c | 32 +++++++++++++++++++++++++++-----
> 1 file changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq_governor.c
> b/drivers/cpufreq/cpufreq_governor.c
> index b1ee597..f158882 100644
> --- a/drivers/cpufreq/cpufreq_governor.c
> +++ b/drivers/cpufreq/cpufreq_governor.c
> @@ -161,9 +161,18 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
> EXPORT_SYMBOL_GPL(dbs_check_cpu);
>
> static inline void __gov_queue_work(int cpu, struct dbs_data *dbs_data,
> - unsigned int delay)
> + unsigned int delay,
> + struct cpufreq_policy *policy)
> {
> - struct cpu_dbs_common_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
> + struct cpu_dbs_common_info *cdbs;
> +
> + if (!dbs_data->cdata) {
> + pr_emerg("common_dbs_data is NULL for %s but initialized = %d",
> + policy->governor->name,
> + atomic_read(&policy->governor->initialized));
> + BUG();
Is it necessary to crash the kernel here?
> + }
> + cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
>
> mod_delayed_work_on(cpu, system_wq, &cdbs->work, delay);
> }
> @@ -185,10 +194,11 @@ void gov_queue_work(struct dbs_data *dbs_data, struct
> cpufreq_policy *policy,
> * those works are canceled during CPU_DOWN_PREPARE so they
> * can't possibly run on any other CPU.
> */
> - __gov_queue_work(raw_smp_processor_id(), dbs_data, delay);
> + __gov_queue_work(raw_smp_processor_id(), dbs_data, delay,
> + policy);
> } else {
> for_each_cpu(i, policy->cpus)
> - __gov_queue_work(i, dbs_data, delay);
> + __gov_queue_work(i, dbs_data, delay, policy);
> }
>
> out_unlock:
> @@ -258,7 +268,13 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
> else
> dbs_data = cdata->gdbs_data;
>
> - WARN_ON(!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT));
> + if (!dbs_data && (event != CPUFREQ_GOV_POLICY_INIT)) {
> + pr_emerg("governor_data is NULL but governor %s is initialized
> = %d [governor_enabled = %d event = %u]\n",
> + policy->governor->name,
> + atomic_read(&policy->governor->initialized),
> + policy->governor_enabled, event);
> + BUG();
And here?
> + }
>
> switch (event) {
> case CPUFREQ_GOV_POLICY_INIT:
> @@ -329,6 +345,12 @@ int cpufreq_governor_dbs(struct cpufreq_policy *policy,
> case CPUFREQ_GOV_POLICY_EXIT:
> mutex_lock(&dbs_data->usage_count_mutex);
> if (atomic_dec_and_test(&dbs_data->usage_count)) {
> + if (atomic_read(&policy->governor->initialized) > 1) {
> + pr_emerg("Removing governor %s but initialized
> = %d, dbs_data->usage_count = 0\n",
> + policy->governor->name,
> + atomic_read(&policy->governor->initialized));
> + BUG();
> + }
> sysfs_remove_group(get_governor_parent_kobj(policy),
> get_sysfs_attr(dbs_data));
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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